1. Field of the Invention
The present invention relates to a substrate treatment apparatus which applies treatment to multiple substrates collectively. Substrates to be subjected to treatment include, for example, semiconductor wafers, liquid crystal display device substrates, plasma display substrates, FED (Field Emission Display) substrates, optical disk substrates, magnetic disk substrates, magneto-optical disk substrates, and photo mask substrates.
2. Description of Related Art
A substrate treatment apparatus which applies treatment using a chemical to substrates such as semiconductor wafers includes a batch type which applies treatment to multiple substrates collectively. An example of the batch type substrate treatment apparatus is shown in Japanese Unexamined Patent Publication No. H11-354604. This substrate treatment apparatus includes a carrier mounting section, a horizontal transfer robot, a posture changing mechanism, a pusher, a conveyance mechanism, and a substrate treatment section.
The carrier mounting section is formed so that a carrier (container) which holds multiple substrates stacked vertically in the horizontal postures is mounted thereon.
The horizontal transfer robot made of a multijoint arm type conveyance robot, and is configured so that a multijoint arm is bent and stretched and swiveled around a vertical axis. Accordingly, the horizontal transfer robot turns the multijoint arm to the carrier and places the vertically stacked multiple substrates in the horizontal postures in and out of the carrier, and further turns the multijoint arm to the posture changing mechanism and receives and delivers the vertically stacked multiple substrates in the horizontal postures from and to the posture changing mechanism.
The posture changing mechanism is for changing the postures of the multiple stacked substrates between the horizontal postures and the vertical postures collectively. To prevent substrate displacement during the substrate conveyance with the multijoint arm, the posture changing mechanism is provided with a substrate alignment mechanism.
The pusher includes a holder vertically and horizontally movable, and can collectively receive and deliver multiple substrates in the vertical postures from and to the posture changing mechanism, and can collectively receive and deliver multiple substrates in the vertical postures from and to the conveyance mechanism. The holder can hold the substrates at a half the pitches of the multiple substrates held by the posture changing mechanism. For example, after 25 substrates are delivered to the holder from the posture changing mechanism, the holder is moved by a minute distance in the horizontal direction along the substrate stacking direction. In this state, another 25 substrates are delivered to the holder from the posture changing mechanism. The 25 substrates delivered later enter among the 25 substrates delivered earlier, and a batch of a total of 50 substrates is formed on the holder. Thus, formation of a batch by combining a plurality of substrate groups is referred to as batch assembly. To deliver the substrates from the pusher to the posture changing mechanism, 25 substrates of the 50 substrates held by the holder are delivered to the posture changing mechanism. After the 25 substrates are changed in posture into the horizontal postures, these are delivered to the horizontal transfer robot. Thereafter, the remaining 25 substrates on the holder are delivered to the posture changing mechanism and changed in posture into the horizontal postures, and then discharged by the horizontal transfer robot. Thus, the 50 substrates are separated into two substrate groups each having 25 substrates. This separation of the multiple substrates forming a batch into a plurality of substrate groups is referred to as batch disassembly.
The conveyance mechanism has substrate chucks which hold multiple substrates forming a batch in the vertical posture, and carries the multiple substrates in and out of the substrate treatment section by moving the substrate chucks horizontally. To clean the substrate chuck, a chuck cleaning unit is provided for example, below a substrate delivery position between the pusher and the conveyance mechanism.
The substrate treatment section has a plurality of treatment tanks arranged along the movement direction of the conveyance mechanism. The treatment tanks include a chemical tank, a wash tank, and a dry tank. In the chemical tank, the multiple substrates in the vertical postures are collectively immersed in a chemical stored in the tank and subjected to a chemical treatment. In the wash tank, the multiple substrates in the vertical postures are collectively immersed in pure water (deionized water) stored in the tank and subjected to washing (rinsing). In the dry tank, treatments such as supply of an organic solvent (for example, isopropyl alcohol) or drainage of liquid components are applied to the multiple substrates collectively.
Major problems in the substrate treatment apparatus of the prior art described above are, first, a low substrate treatment speed (throughput), and second, the expense.
In detail, the horizontal transfer robot is a multijoint arm type, so that its mechanical strength constraint can not increase its moving speed in the state that the robot collectively holds multiple substrates. In addition, the multijoint arm type robot itself is expensive. Further, a space for swiveling the multijoint arm is necessary, so that the area occupied substantially by the apparatus is large.
In addition, when the multijoint arm swivels horizontally, the relative positions of the multiple substrates are displaced. Therefore, as described above, the posture changing mechanism needs to have a substrate alignment mechanism. The operation time of this substrate alignment mechanism strains the substrate treatment speed. In addition to the substrate alignment mechanism, the posture changing mechanism must be provided with a horizontal substrate guide for holding substrates in the horizontal postures, a vertical substrate guide for holding substrates in the vertical postures, and a pivotal mechanism for changing the postures of the substrates, which is an extremely expensive robot.
Further, the pusher includes a vertical movement mechanism, a horizontal movement mechanism, and a rotation mechanism, and is also expensive.
Thus, the time required to convey the substrates between the carrier (container) and the conveyance mechanism contributes to hamper improvement in throughput. The construction for substrate conveyance between the carrier (container) and the conveyance mechanism is expensive, which hampers cost reduction of the substrate treatment apparatus.
In the substrate treatment apparatus of the prior art described above, the substrate conveyance path from the carrier to the conveyance mechanism is one system. Therefore, when untreated substrates are sent into the main conveyance mechanism, treated substrates cannot be discharged from the conveyance mechanism to the carrier, and when treated substrates are discharged, untreated substrates cannot be sent. In addition, when untreated substrates are sent into the conveyance mechanism, a batch assembly operation on the holder of the pusher is necessary, so that the waiting time until discharge of the treated substrates is long. Similarly, when treated substrates are discharged, a batch disassembly operation on the holder of the pusher is necessary, so that the waiting time until reaching the state that untreated substrates can be sent in is also long. This contributes to another cause for lowering in substrate treatment speed.
Further, when the untreated substrates are held by the pusher at a substrate delivery position, the conveyance mechanism cannot discharge treated substrates completely treated in the dry tank to the substrate delivery position. Therefore, first, the conveyance mechanism receives untreated substrates at a substrate delivery position to carry in the chemical tank. Thereafter, the conveyance mechanism cleans the substrate chucks by the chuck cleaning unit, and then receives the treated substrates from the dry tank to deriver to the pusher at the substrate delivery position. Foreign bodies on the surface of the untreated substrates are transferred onto the substrate chucks holding the untreated substrates. Therefore, to prevent the foreign bodies from being transferred onto the treated substrates, the substrate chucks must be cleaned before holding the treated substrates. This contributes to still another cause for lowering in substrate treatment speed.